@Gargron ... I've looked for a possible replacement in comparison reviews and came across this...

shootitwithfilm.com/fuji-super

That led me to look at what the 'new' Fuji 400 could be, and found this...

petapixel.com/2023/04/10/new-f

I get the feeling that Fuji's new 400 could be far different in formula to the old Superia line. If it's actually about scarcity or cost of chemicals to keep making Superia, then perhaps it won't be brought back... just replaced by rebranded Gold or UltraMax.